Jig measuring tool and use of the same

ABSTRACT

This invention is for a jig measuring tool and the method of using the jig measuring tool. The jig measuring tool is of use in aligning gears in a differential, a transmission and final drives in small and large machinery such as small trucks, wheel-type vehicles, crawler vehicles, and industrial material handling machinery and the like. The jig measuring tool makes it possible to save time, save material and to align the gears with greater accuracy in repairing such machinery than with previously available apparatus. Further, it makes it possible for the small repair shops to economically and accurately repair such machinery.

United States Patent 1191 Pieiffer 1 Jan. 14,1975

1 1 JIG MEASURING TOOL AND USE OF THE 21 Appl. No.: 134,987

Related US. Application Data [63] Continuation-in-part of Ser. No.828,610, March 28,

1969, Pat. No. 3,703,769.

[52] US. Cl. 33/181 AT, 29/159 R, 33/178 B [51] Int. Cl. G01b 3/38 [58]Field of Search 33/180 R, 181 R, 180 AT,

33/181 AT, 174 G, 174 H, 178 B; 29/159' FOREIGN PATENTS OR APPLICATIONSGreat Britain 33/178 B Great Britain 33/178 B Germany 33/178 B PrimaryExaminer-William D. Martin, Jr. Attorney, Agent, or Firm-Thomas W.Secrest [57] ABSTRACT This invention is for a jig measuring tool and themethod of using the jig measuring tool. The jig measuring tool is of usein aligning gears in a differential, a transmission and final drives insmall and large machinery such as small trucks, wheel-type vehicles,crawler vehicles, and industrial material handling machinery and thelike. The jig measuring tool makes it possible to save time, savematerial and to align the gears with greater accuracy in repairing suchmachinery than withpreviously available apparatus. Further, it makes itpossible for the small repair shops to economically and accuratelyrepair such machinery.

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PATENTEU JAM 4 mm SHEET 6 OF 6 INVENTOR. l/*2!) D IDFE/FFE/E ATTORNEYJIG MEASURING TOOL AND USE OF THE SAME This application is acontinuation-in-part of my copending patent application Ser. No.828,610, filing date of May 28, 1969, now U.S. Pat. No. 3,703,769,issued Nov. 28, 1972.

Many pieces of equipment, having a differential, transmission or finaldrive, need repairing as the gears may become worn or the gears maybreak or the bearings may become worn and need to be replaced. Anexample, and one with which I am familiar as I have repaired many ofthese units, is the differentials on various half-ton andthree-quarter-ton trucks. These halfton and three-quarter-ton trucks usea Spicer 44 or a Spicer 45 or a Spicer 60 differential. Also, certainmilitary vehicles use a Spicer 35. These differentials are manufacturedby the Spicer Division of the Dana Corporation, Fort Wayne, Ind. andToledo, Ohio. In the repairing or overhauling of such differentials, therear axles were removed, the universal joint leading into thedifferential was disconnected, and the differential and housing weretaken off of the vehicle. Then, the differential and housing were placedon a workstand. If necessary, the housing was spread, due to preloadedbearings, so as to make it possible to remove the differential assembly.The differential assembly was disassembled by removing the bearings,shims and ring gear from the ring gear mounting flange. To examine thepinion gear, bearings, and shims were removed from the housing.

Then, new bearings were pressed on to each end of the differential case,without shims and without ring gear, and the differential case andbearings were positioned in the housing so as to determine the freebasic dimension. This free basic dimension was, and may be taken, with adial indicator. As the differential case bearing assemblies are of thetapered roller type this free basic dimension is essentially anapproximation of the non-preloaded differential test assembly.

The pinion gear was installed in the housing. The depth of the piniongear in the housing could be determined by a pinion depth gauge.However, most repair shops did not have and do not have, a pinion depthgauge and therefore the depth of the pinion gear in the housing was anapproximation.

The differential case assembly with the bearings on each end was removedfrom the housing and the ring gear was mounted on the ring gear mountingflange or the differential case mounting flange. Then, the differentialcase assembly with the ring gear and the bearings was installed, again,in the housing. By means of the dial indicator the position of the ringgear, with respect to the pinion gear, was approximated as to correctbacklash. The ring gear was moved away from the pinion gear and the dialindicator reading of this move ment was taken to give the thickness ofshims to be positioned on the gear side of the differential case, i.e.,the gear side of the differential case being that side of the case onwhich was mounted the ring gear. This was a non-preloaded dimension. Thethickness of shims on the gear side of the differential case wassubtracted from the free basic dimension shim pack to give the thicknessof shims on the off-gear side of the differential case, i.e., that sideof the differential case away from the differential case mounting flangeon the ring gear.

The bearings, which were and are a pressed fit on the differential case,were removed by a bearing puller.

The necessary thickness of shims, in the inboard shim "method, wereinstalled on the differential case plus 0.008 inches of shims on eachside of the differential case. This provided specified preload. Then,the bearings were again pressed onto the hubs of the differential case.

At this stage the housing was spread by means of a special tool, and thedifferential case assembly was once again positioned in the housing. Thehousing was spread to accommodate the preloaded condition of thedifferential case assembly with the bearings and shims on thedifferential case assembly. With the bearings and shims on thedifferential case assembly, the differential case assembly was widerthan the opening leading into the housing and it was necessary to spreadthe housing. In the spreading of the housing a dial indicator wasmounted in such a manner so as to indicate the spread. The maximumallowable speed is 0.020 inches. If the spread is greater than 0.020inches the housing may be permanently distorted. After the differentialcase assembly was installed in the housing the spreader tool was relaxedor removed and bearing caps installed.

At this stage the run out of the ring gear was checked with a dualindicator. If the run out was in excess of 0.002 inches, maximum, it wasnecessary to remove the differential case assembly from the housing.And, the ring gear was removed from the differential case assembly.Then, the differential case assembly was installed in the housing andthe ring gear mounting flange of the differential case was checked witha dial indicator to determine if the differential case was worn ordefective. If a new differential case had to be installed, then the freebasic dimension again had to be determined because of manufacturingtolerances and the variation in dimensions from one'differential case toanother differential case.

The reader is reminded that every time the differential case assembly isinstalled in and removed from the housing, the housing must be spread.

At this stage, the backlash between the pinion gear and the ring gearwas checked to see if there was the specified amount of backlash.

If the backlash between the ring gear and the pinion gear was incorrectthen the differential case assembly was removed from the housing. Thepressed-on bearings were bunches with a puller. In removing the pressedon bearings with the bunches puller the shims were damaged and it wasnecessary to replace the shims. In one repair installation, I had to usenew shims of various thicknesses. New shims were positioned on thedifferential case assembly and the bearings were again presed onto thedifferential case assembly. The differential case assembly with shimsand pressed-on bearings was again positioned in the housing and thebacklash between the ring gear and the pinion gear determined. Thisprocedure was repeated until the correct and specified backlash wasobtained between the ring gear and the pinion gear. Many times it wasnecessary to repeat the steps of removing the differential caseassembly, taking off the bearings with the puller and installing newshims and again pressing on the bearings.

When the correct backlash between the ring gear and pinion gear wasobtained then the correct depth of the pinion gear was determined. To dothis the ring gear teeth were and are painted with a white lead or a redlead and the ring gear and pinion gear were and are rotated to determinethe tooth contact pattern between the ring gear and the pinion gear. Ifthe pattern was incorrect, then the pinion gear, shims, and bearingswere removed from the housing. However, before the pinion gear could beremoved from the housing it was necessary to remove the differentialcase assembly comprising the ring gear, shims and bearings from thehousing. Then, the pinion gear assembly was removed and the necessarycorrections made with respect to the thickness of shims in the innerpinion gear bearing bore.

The pinion gear assembly was installed, once again in the housing. Atthis stage, it must be remembered, that the backlash between the ringgear and the pinion gear had been changed because the thickness of shimson the pinion gear assembly had been changed and the depth of the piniongear in the housing had been changed. Therefore, it was necessary, onceagain, to determine the correct and specified backlash between the ringgear and the pinion gear.

Briefly, any change in pinion depth to correct gear tooth contactpattern resulted in a change in the ring gear and the pinion gearbacklash. In order to return the ring gear and the pinion gear to thespecified backlash it was again necessary to remove the bearings fromthe differential case assembly comprising the ring gear, shims, andbearings. In so removing the bearings a number of shims were againdestroyed. Further, the bearings again had to be pressed onto thedifferential case. Then, it was necessary again to determine the geartooth contact pattern between the ring gear and the pinion gear. If thegear tooth contact pattern was not satisfactory, the entire procedurehad to be repeated until a satisfactory gear tooth contact pattern wassecured. Sometimes, the differential case assembly bearings had to beremoved and replaced five or six times and, it is to be remembered, thateach time the differential case assembly bearings were removed andreplaced it was necessary to use new shims as the shims on thedifferential case assembly were damaged or deformed by pulling thebearings off of the differential case assembly. This was not all.Unfortunately, every once in a while, a bearing was damaged in removingthe bearing from the differential case assembly. It will be found, dueto manufacturing tolerances, that the thickness of the new hearing maybe different from the thickness of the damaged bearing. With thisdifference in thickness there was necessitated a difference in thethickness of shims. This meant that the procedure had to be, virtually,started from the beginning and the entire procedure repeated until theproper backlash and gear tooth contact pattern was secured between thering gear and the pinion gear.

From the foregoing, it is seen that the repairing of a differential ofthis type was an approximation until the correct gear tooth contactpattern was secured between the ring gear and the pinion gear. One ofthe contributing factors to this approximation is the fact that withthis procedure it is not possible to secure a correct determination ofthe preload of the differential case assembly. With this method thepreload condition is, usually, an approximation.

The repair manual allows 7, 7 hours tooverhaul the differentialaccording to this procedure. Of this time, 2.5 hours are allowed forremoving and replacing the differential or rear end from the vehicle.Further, of this 7.7 hours, there are allowed 5.2 hours for overhaulingthe differential or rear end. Sometimes, it is possible to overhaul thedifferential in 5.2 hours and sometimes due to difficulties inapproximating the correct gear tooth contact pattern between the ringgear and the pinion gear and difficulties in pulling the bearings fromthe differential case assembly there is required as long as eight hoursfor overhauling the differential. Actually, when a party starts tooverhaul the differential it is not known if the differential can beoverhauled in the specified 5.2 hours or if a greater period of timewill be required.

Because of the uncertainty of the method of measuring there is thepossibility, when overhaul is completed, that there may be an excessiveor insufficient preload on the differential case assembly bearings. Thisexcessive or insufficient preload will result in premature failure ofthese bearings and possible damage to the housing. From experience, in amajority of those instances where there is insufficient preload there isdamage to the housing and the housing must be replaced. A newdifferential housing is expensive.

As contrasted with the preceding procedure there is briefly outlined theprocedure for repairing a differential using my jig measuring tools andwhich procedure makes possible to more satisfactorily preload thedifferential case assembly bearings.

The housing is spread, either in the vehicle or removed from thevehicle, and the differential case assembly removed, and, also, thepinion gear assembly removed. The pinion gear assembly is disassembledand the differential case assembly is disassembled. All parts arecleaned and examined. The condition of the gears is determined. Then,after determining the pinion gear depth the pinion gear assembly isreinstalled. The differential case assembly, without the ring gearmounted on the ring gear mounting flange, and with jig measuring toolson the differential case assembly, remember, there are no bearingassemblies on the differential case assembly at this stage, thedifferential case assembly is installed in the differential housing todetermine the thickness of shims required. By way of re-capitulation,after the differential case assembly has been removed from the housing,the spreader tension is relieved so as to allow the housing to berelaxed to resume its normal shape. Now, the differential case assembly,without the ring gear and with the jig measuring tools installed on thehubs of the differential cases can be inserted into the housing withoutspreading the housing. The reason for this is that there are no shims onthe differential case assembly at this stage. After adjusting the jigmeasuring tools to eliminate all side-to-side motion while maintainingrotatable clearance the run out of the differential case is checked. Thechecking of the run out of the differential case at this stage of theoverhaul may save considerable time as contrasted with prior procedures.After the run out has been checked the differential case assembly isremoved from the housing, the ring gear installed, and the differentialcase assembly with the ring gear is reinstalled into the housing. lt maybe necessary to readjust the jig measuring tools in order to properlyposition the ring gear. The backlash is determined and the gear toothcontact pattern between the ring gear and the pinion gear is obtained.The differential case assembly with the ring gear is removed from thehousing, and the bearings and shims, plus the thickness of shimsrequired for preload condition as determined from the measurements ofthe jig measuring tools and bearings, are installed on the differentialcase assembly. The readers attention is called'to the fact that this isthe only time that bearings need be positioned on the differential caseassembly. The housing is spread and the differential'case assembly isinstalled in the housing. The bearings caps can be installed and thehousing sealed. This, is the general procedure with the use of mysubject invention, i.e., the jig measuring tool.

From having overhauled differentials and other pieces of machineryhaving gears, it is an object of this invention to provide the jigmeasuring tool so that less labor is required for setting up gears thanrequired with previously available apparatus and methods; to provide amethod using less labor than previous methods have provided, to providea jig measuring tool requiring less time to align gears than priormethods; to provide a jig measuring tool whereby greater accuracy isrealized in measurements for aligning gears; to provide a jig measuringtool making it less expensive to overhaul differentials and gear typemachinery; to provide a jig measuring tool whereby there is no damage toshims and bearings in overhauling a differential and gear typemachinery; to provide a method whereby there is no damage to shims andbearings in overhauling a differential and gear type machinery ascontrasted with prior methods wherein there was damage; to provide amethod and apparatus for more satisfactorily preloading thedifferential; to provide a jig measuring tool and a method which makesit possible to have a preview of the entire overhaul of the differentialbefore bearings and shims are placed on the differential case assembly;to provide a method and apparatus for determining the run out of adifferential case previous to final assembly; and, to provide a jigmeasuring tool which makes it possible to have better gear tooth contactbetween the gears in a differential and in gear type machinery.

These and other important objects and advantages of the invention willbe more particularly brought forth upon reference to the accompanyingdrawings, the detailed description of the invention and the appendedclaims.

In the drawings:

FIG. 1 is a fragmentary, partial side elevational view and partialvertical cross-sectional view, of a specific embodiment of a jigmeasuring tool and shows the stationary member and the movable membermounted on said stationary member;

FIG. 2 is an end elevational view of the jig measuring tool of FIG. 1and illustrates a movable member mounted on the stationary member;

FIG. 3 is an exploded side elevational view illustrating the stationarymember and the movable member;

FIG. 4 is a partial side elevational view and a partial verticalcross-sectional view of another embodiment of the jig measuring tool andillustrates the stationary member and the movable member mounted on saidstationary member;

FIG. 5 is an end elevational view of said jig measuring tool of FIG. 4and illustrates the movable member mounted on said stationary member;

FIG. 6 is an exploded view of the jig measuring tool of FIG. 4 andillustrates the stationary member and the movable member;

FIG. 7 is a partial side elevational view and a partial verticalcross-sectional view of another jig measuring tool and illustrates thestationary member and the movable member mounted on said stationarymember;

FIG. 8 is an end elevational view of said jig'measuring tool of-FIG. 7and illustrates the movable member mounted on said stationary member;

FIG. 9 is an exploded view of the jig measuring tool of F167 andillustrates the stationary member and the movable member;

FIG. 10 is a vertical longitudinal cross-sectional view of anotherspecific embodiment of a jig measuring tool and illustrates an outerstationary member and an inner movable member mounted in said outerstationary member;

FIG. 11 is an end elevational view of said jig measur ing tool of FIG.10 and illustrates said inner movable member mounted in said outerstationary member;

FIG. 12 is a side elevational view of the outer stationary member;

FIG. 13 is a side elevational view of the inner movable member;

FIG. 14 is a fragmentary, partial cross-sectional view of a differentialand illustrates the pinion gear assembly, the differential caseassembly, and two methods for adjusting the differential case assembly,one by the inboard shims, on the left of the differential case assembly,the other by the outboard shims, on the right of the differential caseassembly and the differential housing;

FIG. 15 is a fragmentary, partially in longitudinal verticalcross-section, of a differential case with the jig measuring tool ofFIGS. 1, 2,. and 3 on the left, and with the jig measuring tool of FIGS.4, 5, and 6 on the right;

FIG. 16 is a fragmentary longitudinal vertical crosssectional view of adifferential case and with the jig measuring tools of FIGS. 7, 8, and 9;

FIG. 17 is a view, partially in phantom and partially in cross-section,of a preloaded differential case assembly with ring gear, with bearingsand with inboard shims, and illustrates in a fragmentary cross-sectionalview, the differential housing spread so that the opening in the housingwill accommodate the preloaded differential case assembly with bearings;

FIG. 18 is a view showing the differential case without the ring gearand with two bearing assemblies, without shims on the differential case,to illustrate the variable dimension in the width of the bearingassemblies of the differential case assembly;

FIG. 19 is a fragmentary, partial cross-sectional view I of thedifferential case test assembly, different embodiments of the jigmeasuring tools and illustrating some of the basic dimensions of thedifferential case test assembly and the differential housing; and,

FIG. 20 is a view if the differential housing and looking into theinterior of the housing and illustrates the pinion gear, thedifferential case test assembly positioned in jig measuring tools in thedifferential housing, and illustrates, in phantom, a spreader tool forspreading the differential housing so as to make the opening into thedifferential housing larger in order to accommodate a preloadeddifferential case assembly.

In FIGS. 113 there is illustrated four jig measuring tools. I

In FIGS. 1-3 there is illustrated a first jig measuring tool 30. Thetool 30 comprises a stationary member 32 and a movable member 34. Thestationary member 32 has an outside surface 36 of a diametricaldimension which is substantially the same as, but slightly less than,the interior diametrical dimension of a bearing bore and in which boresaid stationary member 32 will be positioned. The stationary member 32has a circular body portion 38 and on one side a circular shoulder 40which is externally threaded. The stationary member 32 and the movablemember 34 have a center line 42 and which center line is a center lineof the outside diametrical dimension for the stationary member 32 andthe movable member 34. This center line will substantially coincide withthe center line of said bearing bore when said jig measuring tool ispositioned in said bearing bore. The center line also substantiallycoincides with the center line of the differential case. The stationarymember 32 has a central bore 44. The center line of the jig measuringtool is also the center line of the central bore 44. The interiordiametrical dimension of the central bore is slightly larger than theexterior diametrical dimension of a first bearing surface on which thejig measuring tool will be positioned. The first bearing surface beingthe differential case hubs on which the jig measuring tool will bepositioned. This provides a rotatable clearance between the jigmeasuring tool and the first bearing surface. The stationary member 32has a first exterior surface 46 and a second exterior surface 48. Theexterior surface 48 is positioned adjacent to the exterior threadedcircular shoulder 40. In the exterior surface 36 there are a number ofholes 50. The stationary member 32 is chamfered at 52 at the junction ofthe surface 36 with the side 46 and also at the junction of the surface36 with the side 48. Also, the entrance to the central bore is chamferedat 54, both ends of the central bore.

The movable member 34 is essentially a split ring having a parting lineor surface 56 from the outer diametrical surface 58 to the internallythreaded bore 60. On one side the parting line 56 there is a recess 62and a passageway 64. On the other side of the parting line 56 there is adrilled and threaded hole 66. A setscrew 68 is positioned in the recess62, the passageway 64 and the drilled and threaded hole 66. Also, on theexterior diametrical surface 58 there are a number of holes 70 forreceiving a tool so as to rotate the movable member 34 on the threadedcircular shoulder 40 of the stationary member 32. The holes 50 on thestationary member 32 make it possible to prevent rotation of thestationary member 32 while rotating the movable member 34 thereon.

It is seen that the setscrew 68 may be loosened, the rotatable member 34rotated on the exterior threaded circular shoulder 40 to a desiredposition, and then the setscrew 68 turned so as to tightly and firmlyposition the movable member 34 with respect to the stationary member 32.

The movable member 34 has sides 72. Also, the movable member 34 ischamfered at 74 at the junction of the diametrical surface 34 and thesides 72.

The exterior diametrical dimension of the movable member 34 may besubstantially the same as the exterior diametrical dimension of thestationary member 32 or may be slightly less than the exteriordiametrical dimension of the stationary member 32.

In FIGS. 4, 5, and 6, there is illustrated a second jig measuring tool80. This jig measuring tool 80 comprises a stationary member 32, whichhas previously been described, and a movable member 82. The movablemember 82 is of a generally ring-like configuration and has an exteriordiametrical surface 84, a central bore 86, and sides 88. In the exteriordiametrical surface 84 there are four drilled and threaded passagewaysextending from the exterior diametrical surface 84, through the body ofthe movable member 82, and to the internally threaded bore 86. There ispositioned in each drilled and tapped passageway 90 a positioning meanscomprising a plug 92, a spring 94 and a setscrew 96. This is africtional lock. The frictional lock is controlled by the adjustment ofsaid setscrews 96. In the exterior diametrical surface 84 there are aplurality of drilled holes 98. It is possible to place a tool in a hole98 so as to rotate the movable member 82 on the externally threadedcircular shoulder 40. The dimension of the exterior diametrical surface84 may be substantially the same as the dimension of the exteriordiametrical surface 36 of the movable member 32 or maybe slightly lessthan the dimension of the exterior diametrical surface 36 of the movablemember 32. The jig measuring tool 80 has a center line 100. The centerline 100 of the jig measuring tool is also the center line of thecentral bore 44. The interior diametrical dimension of the central boreis slightly larger than the exterior diametrical dimension of a firstbearing surface on which the block will be positioned, and which firstbearing surface is the hub of the differential case. This provides arotatable clearance between the jig measuring tool and the first bearingsurface. The movable member 82 is chamfered at 102, the junction of theoutside diametrical dimension 84 and the sides 88.

In FIGS. 7, 8 and 9 there is illustrated a third jig measuring tool 110.The jig measuring tool comprises a stationary member 112 and a movablemember 114. The stationary member 112 has an outside surface 113 of adiametrical dimension which is substantially the same as, but slightlyless than, the interior diametrical dimension of a bearing bore and inwhich bore said jig measuring tool will be positioned. Further, said jigmeasuring tool has a center line 116 and which center line is a centerline of said outside diametrical dimension of the stationary member 112.The center line 116 will substantially coincide with the center line ofsaid bearing bore when said jig measuring tool is positioned in saidbearing bore. The stationary member 112 has a central bore 118. Thecenter line of the jig measuring tool is also substantially the centerline of the central bore 118. The interior diametrical dimension of thecentral bore 118 is slightly larger than the exterior diametricaldimension of a first bearing'surface on which said jig measuring toolwill be positioned. This first bearing surface may be the hubs of adifferential case. This provides a rotatable clearance between the jigmeasuring tool and the first bearing surface. The stationary member 112has a circular shoulder 120. Also, the stationary member 122 has a firstexterior surface 122 and a second exterior surface 124. The secondexterior surface 124 is adjacent to the circular shoulder 120. Thecircular shoulder has a smoolh exterior surface 126. The stationarymember 112 is chamfered at 128, the junction of the surface 113 and theside 122. Also, the stationary member 112 is chamfered at 130, thejunction of the surface 113 and the side 124. Further, the central bore118 is chamfered at 132, on both ends of the central bore.

The movable member 114 has a generally ring-like or annularconfiguration and has a body 136, also, 1 14 has sides 138 and anexterior diametrical surface 140. The movable member 114 is chamfered at142, the junction of the side 138 and the exterior diametrical dimension140. In the body 136 there is a drilled and tapped passageway 144extending from the exterior diametrical dimension 140 to the centralbore 146. In the drilled and tapped passageway 144 there is a setscrew148 for firmly positioning the movable member 114 onto the circularshoulder 120 of the stationary member 112. The bore 146 is of a slightlygreater interior diameter than the exterior diameter of the circularshoulder 120. Also, the center line 116 of the bore 146 is substantiallythe center line of the movable member 114 and also of the exteriordiametrical surface 140. This makes it possible for the movable member114 to slip onto the move on the circular shoulder 120.

In FIGS. 10, 11, 12 and 13 there is illustrated a jig measuring tool150. This tool comprises a stationary member 152 and a movable member154.

In the side elevational view, the stationary member 152 has theappearance of a torus. Also, in a side elevational view, the movablemember 154 has the appearance of a torus.

The stationary member 152 is of a generally cylindrical configurationand has a smooth exterior surface 156 and a threaded central passageway158.

There is a tapped drilled hole 160 extending from the surface 156 to thethreaded passageway 158. In the tapped drilled hole 160, there ispositioned a setscrew 162.

The stationary member 152 has sides 164. At the junction of the sides164 and the exterior surface 156 there is a chamfered edge 166.

The movable member 154 has a first externally threaded surface 170 and asecond externally threaded surface 172. Between the threaded surfaces170 and 172 there is a recessed smooth surface 174. The recessed smoothsurface 174 is of a lesser external diameter than the external diametersof the threaded surfaces 170 and 172. I

The movable member 154 has a further external surface 176. The surface176 is of a lesser external diameter than the external diameter of thethreaded surface 172.

In the external surface 176, and at, approximately, 90 intervals thereare four recesses 178.

The movable member 154 has a first side 180, adjacent to the externallythreaded surface 170, and a second side 182, adjacent to the externalsurface 176.

The movable member 154 has a smooth central passageway 184. At thejunction of the side 180 and the passageway 184 there is a chamferededge 186. At the junction of the side 182 and the passageway 184 thereis a chamfered edge 188. In FIGS. and 13 it is seen that the externallyrecessed surface 174 is positioned between the externally threadedsurfaces 170 and 172. The width of the externally recessed surface 174is sufficient to allow the movable member 154 to be partially screwedinto and out of the stationary member 152.

Also, it is seen that is is possible for the setscrew 162 to be screwedinto the drilled tapped hole 160 so as to firmly position the movablemember 154 and the stationary member 152 with respect to each other.

The stationary member 152 has the outside surface 156 ofa diametricaldimension which is substantially the same as, but slightly less than,the interior diametrical dimension of a bearing bore and in which saidbore said stationary member 152 will be positioned. It is to beremembered that the movable member 154 will be positioned in thestationary member 152.

The stationary member 152 has a center line 190 and which center line isa center line of said outside diametrical dimension of the surface 156.This center line 190 will substantially coincide with the center line ofsaid bearing bore when said stationary member 152 is positioned in saidbearing bore. Again, the stationary member 152 has a threaded passageway158. The center line of the stationary member 152 is also the centerline of the threaded passageway 158. The movable member 154 has anexterior diametrical dimension of the exteriorally threaded surfaces 170and 172. The movable member 154 has a center line which, when themovable member 154 is positioned in the stationary member 152, coincideswith the center line 190, and will be referred to by reference numeral190. The movable member 154 has an interior surface 184, and which isthe interior diametrical dimension of this interior surface 184 orpassageway 184. The center line of the interior passageway 184 is thecenter line 190. The interior diametrical dimension of the passageway orcentral bore 184 is slightly larger than the exterior diametricaldimension of a first bearing surface on which the movable member 154will be positioned. This provides a rotatable clearance between the jigmeasuring tool 150, or the movable member 154 and the first bearingsurface. The jig measuring tool is of a variable width, depending uponthe position of the movable member 154 with respect to the stationarymember 152, and which variable width will be substantially equal to thewidth of a bearing assembly plus the necessary shims and for which saidbearing assembly and said shims said jig measuring tool 150 will betemporarily substituted in said bearing bore and on said bearingsurface.

The drilled holes 178 in the movable member 154 are for receiving a toolso that the movable member may be moved or adjusted with respect to thestationary member 152.

In FIG. 14 there is a fragmentary cross-sectional view of a differentialhousing 200 having an integral pinion gear and shaft 202. On the outerend of the pinion gear shaft 202 there is a pinion gear yoke 204.

In the housing 200 there are spaced-apart bearing bores 206 and 208 forreceiving an outer bearing 210 for the pinion gear 202 and an innterbearing 212 for the pinion gear 202. In FIG. 14 it is seen that thereare shims 214 between a circular shoulder 216 and the bearing 208 so asto position the bearing 212 and the pinion gear 202 in the bearing bore208. The function of the shims 214 will be more particularly describedin a later part of the specification.

Also, in the housing 200, it is seen that there are two spaced apartdifferential case bearing bores 220 and 222. The bearing bore 220 is onthe gear side of the differential case and the bearing bore 222 is onthe off gear side of the differential case. In the bearing bore 220there is a bearing 224 and in the bearing bore 222 there is a bearing226. The bearings 224 and 226 are pressed onto the hubs 228 and 230 ofthe differential case 232. The hub 228 is on the gear side of thedifferential case and the hub 230 is on the off gear side of thedifferential case. The differential case has a ring gear mounting flange234. On the ring gear mounting flange 234 there is mounted a ring gear236 and which ring gear 236 is secured by bolts to the ring gearmounting flange 234.

With reference to FIG. 14 the reader is to realize that this is aschematic illustration of a differential having both an inboard shim 238and an outboard shim 240. In a differential, the differential will haveeither an inboard shim or an outboard shim but will not have thecombination of an inboard shim 238 and an outboard shim 240 asillustrated in FIG. 14. Again, FIG. 14 is a schematic illustration toshow that a differential may have inboard shims as illustrated byreference numeral 238 or may have outboard shims as illustrated byreference numeral 240.

In FIG. 19 A represents the normal opening in the differential housing200. This opening is a variable dimension due to manufacturingtolerances. Normally, in assembling a differential case assembly, withinboard shims, the dimension of the differential case assembly is largerthan the dimension of the opening A. Therefore, a spreader tool 201 isrequired to enlarge the opening A by approximately 0.020 inches. It isadvisable to not spread the opening A by more than 0.020 inches in orderto avoid permanent distortion of the differential housing 200. The useof a spreader tool 201 to enlarge the opening A is normal and has beenused for many years.

The dimension B is the overall length of the differential case testassembly with the jig measuring tools positioned and adjusted on thehubs. The dimension B is approximately equal to but slightly less thanthe dimension A so as to provide rotatable clearance between thedifferential case test assembly and the jig measuring tools.

The dimensions I and J are variable in order to place the ring gear 236in its proper position relative to the pinion gear 202 to obtainspecified backlash between the ring gear 236 and the pinion gear 202.The dimension I is the off-gear side dimension between the differentialcase and the shoulder of the bearing bore 222 of the differentialhousing. The dimension J is the gear side dimension between thedifferential case and the shoulder of the bearing bore 220 of thedifferential housing.

The dimension E is the overall length of the differential case, lesshubs, and is a variable due to the manufacturing tolerances.

Because of the variations in the manufacturing tolerances of thedimension A, the dimension B, the dimension E, see FIG. 19, and thevariation in the thickness of the bearing assemblies 228 and 230, seeFIG. 14, it is necessary to use shims of various thickness in order toobtain specified backlash between the ring gear and the pinion gear andalso to obtain necessary preload of the differential case assembly.

The jig measuring tool, 30, 80, 110 or 150 is adjustable in thicknessbecause of the two relatively movable members. The reason for theadjustability, with respect to thickness, is to determine the dimensionsI and J. From these dimensions it is possible to figure the properadjustment of the differential. Further, from these dimensions it ispossible to figure the correct thickness of shims required for thenompreloaded state or the non-preloaded condition of the differentialcase test assembly.

In FIG. 14 there is illustrated the dimension F. The dimension F is theshortest dimension between the bearing bore 220 or 222 and the innersurface of the cylindrical wall 216 of the pinion gear bearing bore 208.The dimension F is an accurate dimension and does not vary more that0.000,5 inches. In other words, the maximum variation in the dimension Ffrom one differential housing 200 to another differential housing 200 is0.001 inches.

In the pinion gear 202 there is a variation in the depth of the gearteeth due to the manufacturers tolerance. The variation will run from i0.006 inches. This is marked on the pinion gear 202 so that the partyassembling the differential will have a reference dimension. Then, theproper thickness of the shims 214 can be used to approximately correctfor the variation in the ,manufacture of the pinion gear 202. Thedimension mark on the pinion gear 202 indicates whether the pinion gearwill extend farther into the housing or not as far into the housing. Theshims 214 are necessary to make corrections for this dimension to havethe pinion gear 202 positioned properly in the differential housing 200.

Again, with reference to FIG. 19, it is seen that there is adifferential case test assembly 250 having a jig measuring tool on a hub228 and a jig measuring tool 150 on a hub 230. The thickness of the jigmeasuring tool 150, i.e., determined by the relative positions of thestationary member 152 and the movable member 154, determines, where thedifferential case test assembly is positioned in the differentialhousing 200, i.e., the relative position of the ring gear 236 withrespect to the pinion gear 202. It is possible by adjusting thicknessesof the jig measuring tools 150 on the hubs 228 and 230 to obtain thespecified backlash. More particularly, the differential case testassembly 250 is installed in the differential case bearing bores 220 and222 and in the differential housing 200. In this regard, see FIG. 20.The backlash between the ring gear 236 and the pinion gear 202 ischecked to determine if there is specified backlash between these twogears. If the backlash is incorrect then the thickness of the jigmeasuring tools 150 on the hubs 228 and 230 is adjusted to secure thespecified backlash. After the specified backlash is secured then thegear tooth contact between the pinion gear 202 and the ring gear 236 ischecked to determine the correct depth of the pinion gear 202 in thehousing 202 and with respect to the ring gear 236. The gear toothcontact pattern between the ring gear and the pinion gear is visuallydetermined by painting red lead or white lead or other suitable visualindicator on the ring gear teeth and rotating the ring gear so as tohave the ring gear teeth contact the teeth of the pinion gear. Ifnecessary, the depth of the pinion gear in the housing is changed tohave the correct gear tooth contact pattern between the pinion gear andthe ring gear.

Then, the differential case test assembly 250 is removed from thedifferential housing 200. The jig measuring tools 150 are removed fromthe differential case test assembly 250. The thickness of a bearing 226assembly with respect to the thickness of the jug measuring tool on theoff-gear side is determined. This makes it possible to determine thethickness of shims necessary for the off-gear side of the differentialcase assembly, for a non-preloaded condition. Likewise, the thickness ofa bearing assembly 264 with respect to the thickness of a jig measuringtool on the gear side of the differential case test assembly isdetermined. This makes it posssible to determine the thickness of theshims required on the gear side of the differential case assembly, for anon-preloaded condition. Then, the differential case assembly ispreloaded. The preload can vary from 0.006 inches to 0.008 inches ofshims on each hub 228 and 230 of the differential case 200, but

must be of equal thickness on both hubs. It is called to the attentionof the reader that the thickness of the preload shims, approximately0.006 inches to about 0.008 inches is in addition to the thickness ofshims previously determined for the differential case 200. Then, theappropriate shims and bearing assembly are pressed onto the hubs 228 and230 to form the preloaded differential case assembly.

In FIG. 17 there is illustrated a preloaded differential case assembly260v having bearing assembly 262 with appropriate shims 266 on the hub228 and bearing assembly 264 with appropriate shims 268 on the hub 230.

As recalled A represents the normal opening in the differential housing200. A AA represents the normal opening in the differential housing 200plus the spread of the opening in the housing, the spread of the openingbeing approximately 0.020 inches, so as to accommodate the preloadeddifferential case assembly 260.

Dimension C is the off-gear side shim dimension between the bearingassembly 262 and the differential case 232. The dimension X is thethickness of the shims for the preloaded condition normally in the rangeof 0.006 inches to 0.008 inches. The dimension C X is the preloaded shimdimension between the bearing assembly 262 and the differential case232.

The dimension D is the gear side dimension between the bearing assembly264 and the differential case 232. The dimension Y is the thickness ofshims for the preloaded condition normally, in the range of 0.006 inchesto 0.008 inches. The dimension D -l- Y is the preloaded shim dimensionfor the gear side dimension between the bearing assembly 264 and thedifferential case 232.

As is recalled to the dimension X is equal to the dimension Y so thatthe thickness of the preload shims is the same on each side of thedifferential case assembly 260.

The dimension B X Y is the preloaded overall length of the differentialcase assembly 260 with inboard shims 266 and 268 and the bearingassemblies 262 and 264 on the hubs 228 and 230.

It is necessary to determine the thickness of the bearing assembly 262or 264 with respect to the thickness of the jig measuring tool 150. Inthe manufacture of the bearing assemblies 262 and 264, the thickness ofthe bearing assembly varies. This variation in the thickness of thebearing assemblies may be as much as plus or minus, 0.006 inches. Inthis regard, see FIG. 18, and hearing assemblies G and H. In almost allinstances, the thickness of the bearing assembly G will be differentthan the thickness of the bearing assembly R. It is because of thevariation in the thickness of the bearing assemblies and othermanufacturing variations for the ring gear and the pinion gear, thedifferential housing and the differential case, that the jig measuringtools and the method for using such jig measuring tools have value. Torepeat, with the prior methods of overhauling a differentiaal usinginboard shims, as well as outboard shims, bearing assemblies werepressed on to the hubs 228 and 230 on the differential case 232 .to makethe differential case assembly 260. The steps of determining the freebasic dimension, the specified backlash and the correct gear toothcontact pattern necessitated, the

forceful removal or pulling off of the bearing assem-' blies 262 and 264from the hubs 228 and 230. With the 6 264 were so badly damaged ordestroyed that the hear- I ing assemblies had to be discarded. Then, itwas necessary to use another bearing assembly. As the thickness of thebearing assemblies varied, this necessitated, once again, thedetermination of the free basic dimension and the correct gear toothcontact pattern between the ring gear and the pinion gear, From this,you can see that the shims were destroyed and bearing assemblies,possibly, damaged. As contrasted with this my jig measuring tools andmethods for using the same make it possible to position the jigmeasuring tools on the hubs 228 and 230 by hand and without the use of atool to force the jig measuring tools onto the hubs. Likewise, the jigmeasuring tools can be removed by hand and without a tool, from the hubs228 and 230. Further, my method and jig measuring tools make it possibleto more quickly remove the jig measuring tools from the hubs asmechanical means are not required.

With the use of my jig measuring tools 30 or or or it is also possibleto have the shims on the outside of the bearings 262 and 265. Place theshims 240, see FIG. 14, on the outside of the bearing 226. Remember, thebasic dimensions have already been determined for the thickness of theshims required with-the bearings 262 and 264. Then, the proper preloadof approximately 0.006 to about 0.008 inches can be added to thethickness of the shims and the shims, 240, placed on the outside of thebearings 262 and 264. This makes it possible to have the properthickness of shims for an outboard shim differential case assembly.

In the outboard shim method of assembling a differential case assembly,there is used only one shim instead of a shim pack, as in an inboardshim method in assembling a differential case assembly. For example, thethickness of shimsin the differential case assembly having outboardshims varies as follows: the thickness of the shims varies from 0.060inches to 0.095 inches in increments of 0.001 inches. Therefore, onlyone shim is placed in each differential housing bearing bore 220 and 222between the bearing on the hub of the differential case assembly and thehearing bore. As contrasted with this, in an inboard shim method, theshims 266 and 268 are available in thicknesses of 0.003 inches, 0.005inches, 0.010 inches and 0.030 inches. Generally, in the inboard shimmethod, there is used a multiplicity of shims 266 and 268. By variouscombinations of these shims in the inboard shim method the desiredthickness of the shims is realized, including the desired preloadthickness of shims.

With the foregoing presentation of the detailed description of theinvention, I herewith claim the following:

1. A jig measuring tool for securing rapid and accurate clearancemeasurement, said tool comprising:

a. a first member of a generally annular configuration whose outsidediametrical dimension is substantially the same as but slightly lessthan the interior diametrical dimension of a bearing assembly bore andin which bore said first member will be posi tioned;

b. said first member having a center line and said center line being thecenter line of said outside diametrical dimension and said center linealso substantially coinciding with the center line of said bearingassembly bore when said first member is positioned in said bore;

c. said first member with its generally annular configuration having afirst central bore;

said center line of said first member being the center line of saidfirst central bore;

e. a second member of a generally annular configuration;

f. said second member with its generally annular configuration having asecond central bore;

g. said second member having a center line and said center line beingthe center line of said second central bore;

h. said first member and said second member mate with each other and arecapable of adjustment relative to each other along said center lines;

i. a first means to fixedly position said first member and said secondmember with respect to each other;

j. said first member and said second member comprising said tool;

k. said tool having a central bore having an interior diametricaldimension substantially the sme as but slightly larger than the exteriordiameter dimension of the first bearing surface on which the tool willbe positioned so as to provide a rotatable clearance between said tooland said first bearing surface;

and,

1. said tool having a width approximately equal to the width of abearing asssembly for which said bearing assembly said tool will betemporarily substituted in said bearing assembly bore and on saidbearing surface.

2. A jig measuring tool according to claim 1 and comprising:

a. said first member on its outer annular surface and said second memberon its outer annular surface having means to adjust said first memberand said second member relative to each other.

3. A jig measuring tool according to claim 1 and comprising:

a. said first member on one side having a shoulder;

b. said shoulder having a first exterior diameter; and,

c. the interior diameter of said second central bore being of a slightlylarger dimension than the dimension of said first exterior diameter toallow said first member and said second member to mate and to moverelative to each other.

4. A jig measuring tool according to claim 3 and comprising:

a. said shoulder having exterior threads; and,

b. said second central bore having internal threads.

5. A jig measuring tool according to claim 4 and comprising:

a. said second member being discontinuous and having a radial separationto define a split ring; and, b. a second means to maintain position ofsaid second member on said first member.

6. A jig measuring tool according to claim 5 and comprising:

a. said second means comprising a fastening device extending on bothsides of said separation to provide a means for the clamping of saidsecond member on said first member.

7. A jig measuring tool according to claim 4 and comprising:

a. a second means to maintain the position of said second member on saidfirst member.

8.A jig measuring tool according to claim 7 and comprising:

a. said second means comprising a passageway in said second means andextending from the outer annu- 5 lar surface to the inner annularsurface; and,

b. means in said passageway to position said second member on said firstmember.

9. A jig measuring tool according to claim 4 and comprising:

a. a second means to maintain the position of said second member on saidfirst member; and,

b. a plug, a spring and a set screw in said passageway to provide africtional load to maintain position of said second member on said firstmember.

10. A jig measuring tool according to claim 3 and comprising:

a. a second means to maintain the position of said second means on saidfirst means.

11. A jig measuring tool according to claim 10 and comprising:

a. said second means comprising a passageway in said second means andextending from the outer annular surface to the inner annular service;and,

b. means in said passageway to position said second means on said firstmeans.

12. A jig measuring tool according to claim 3 and comprising:

a. a second means to maintain the position of said second member on saidfirst member; and,

b. a plug, a spring and a set screw in said passageway to provide africtional load to maintain position of said second member on said firstmember.

13. A jig measuring tool according to claim 1 and comprismg:

a. said second member capable of moving in said first member; and,

b. a second means to maintain the position of said first member on saidsecond member.

14. A jig measuring tool according to claim 1 and comprising:

a. the interior diameter of said first central bore of said first memberbeing of a slightly larger dimension than the exterior dimension of saidsecond member so as to allow said first member and said second member tomate and to move relative to each other; and,

b. a second means to maintain the position of said first member on saidsecond member.

15. A jig measuring tool according to claim 14 and comprising:

a. the central bore of said first member having interior threads; and, j

b. said second member having exterior threads.

16. A jig measuring tool according to claim 14 and comprising:

a. said second member having a recess;

b. said first member having a passageway from the outer annular surfaceto the inner annular surface;

and,

c. a means in said passageway and in said recess to maintain theposition of said first member on said second member.

17. A jig measuring tool according to claim 15 and comprising:

a. said second member having a circular recess;

-17 18 b. said first member having a passageway from the comprising:

Outer annular Surface 9 the annular Surface; a. said first member beingsubstantially flat on both and,

c. a set screw in said passageway and in said recess to maintain theposition of said first member on Sald ec0nd member bemg Substanuany flaton said second member. both Sldes- 18. A jig measuring tool according toclaim 14 and sides; and

1. A jig measuring tool for securing rapid and accurate clearancemeasurement, said tool comprising: a. a first member of a generallyannular configuration whose outside diametrical dimension issubstantially the same as but slightly less than the interiordiametrical dimension of a bearing assembly bore and in which bore saidfirst member will be positioned; b. said first member having a centerline and said center line being the center line of said outsidediametrical dimension and said center line also substantially coincidingwith the center line of said bearing assembly bore when said firstmember is positioned in said bore; c. said first member with itsgenerally annular configuration having a first central bore; said centerline of said first member being the center line of said first centralbore; e. a second member of a generally annular configuration; f. saidsecond member with its generally annular configuration having a secondcentral bore; g. said second member having a center line and said centerline being the center line of said second central bore; h. said firstmember and said second member mate with each other and are capable ofadjustment relative to each other along said center lines; i. a firstmeans to fixedly position said first member and said second member withrespect to each other; j. said first member and said second membercomprising said tool; k. said tool having a central bore having aninterior diametrical dimension substantially the sme as but slightlylarger than the exterior diameter dimension of the first bearing surfaceon which the tool will be positioned so as to provide a rotatableclearance between said tool and said first bearing surface; and, l. saidtool having a width approximately equal to the width of a bearingasssembly for which said bearing assembly said tool will be temporarilysubstituted in said bearing assembly bore and on said bearing surface.2. A jig measuring tool according to claim 1 and comprising: a. saidfirst member on its outer annular surface and said second member on itsouter annular surface having means to adjust said first member and saidsecond member relative to each other.
 3. A jig measuring tool accordingto claim 1 and comprising: a. said first membEr on one side having ashoulder; b. said shoulder having a first exterior diameter; and, c. theinterior diameter of said second central bore being of a slightly largerdimension than the dimension of said first exterior diameter to allowsaid first member and said second member to mate and to move relative toeach other.
 4. A jig measuring tool according to claim 3 and comprising:a. said shoulder having exterior threads; and, b. said second centralbore having internal threads.
 5. A jig measuring tool according to claim4 and comprising: a. said second member being discontinuous and having aradial separation to define a split ring; and, b. a second means tomaintain position of said second member on said first member.
 6. A jigmeasuring tool according to claim 5 and comprising: a. said second meanscomprising a fastening device extending on both sides of said separationto provide a means for the clamping of said second member on said firstmember.
 7. A jig measuring tool according to claim 4 and comprising: a.a second means to maintain the position of said second member on saidfirst member.
 8. A jig measuring tool according to claim 7 andcomprising: a. said second means comprising a passageway in said secondmeans and extending from the outer annular surface to the inner annularsurface; and, b. means in said passageway to position said second memberon said first member.
 9. A jig measuring tool according to claim 4 andcomprising: a. a second means to maintain the position of said secondmember on said first member; and, b. a plug, a spring and a set screw insaid passageway to provide a frictional load to maintain position ofsaid second member on said first member.
 10. A jig measuring toolaccording to claim 3 and comprising: a. a second means to maintain theposition of said second means on said first means.
 11. A jig measuringtool according to claim 10 and comprising: a. said second meanscomprising a passageway in said second means and extending from theouter annular surface to the inner annular service; and, b. means insaid passageway to position said second means on said first means.
 12. Ajig measuring tool according to claim 3 and comprising: a. a secondmeans to maintain the position of said second member on said firstmember; and, b. a plug, a spring and a set screw in said passageway toprovide a frictional load to maintain position of said second member onsaid first member.
 13. A jig measuring tool according to claim 1 andcomprising: a. said second member capable of moving in said firstmember; and, b. a second means to maintain the position of said firstmember on said second member.
 14. A jig measuring tool according toclaim 1 and comprising: a. the interior diameter of said first centralbore of said first member being of a slightly larger dimension than theexterior dimension of said second member so as to allow said firstmember and said second member to mate and to move relative to eachother; and, b. a second means to maintain the position of said firstmember on said second member.
 15. A jig measuring tool according toclaim 14 and comprising: a. the central bore of said first member havinginterior threads; and, b. said second member having exterior threads.16. A jig measuring tool according to claim 14 and comprising: a. saidsecond member having a recess; b. said first member having a passagewayfrom the outer annular surface to the inner annular surface; and, c. ameans in said passageway and in said recess to maintain the position ofsaid first member on said second member.
 17. A jig measuring toolaccording to claim 15 and comprising: a. said second member having acircular recess; b. said first member having a passageway from the outerannular surface to the inner annular surface; and, c. a set screw insaid passageway and in said recess to maintaiN the position of saidfirst member on said second member.
 18. A jig measuring tool accordingto claim 14 and comprising: a. said first member being substantiallyflat on both sides; and b. said second member being substantially flaton both sides.